Instancing Lights - Corona 5 (Daily Build 2019-09-20)

[Exactly]

Hi Corona Team,

Great work on getting Corona working with R21...thanks :-)

Each time a daily build comes out I end up testing the same scene (attached) to see how things are coming along with instancing lights. But the results have always been the same.
If you look at the attached scene, just select the 3 cloners and change the instance modes.
Then compare the IR and VFB/PV.

I know there is a lot of talk about Scatter and multi instancing but I am really finding it hard to work with a lack of render instances when it comes to lights. Of course multi instance support would been even more appreciated!
I use hundreds of lights in the type of work I do and I have two options at present...

1) Set all cloned lights to Instance mode and then have to deal with the usual speed issues associated with that.
2) Set all cloned lights to Render Instances modes and work with IR ok but have to change all cloned lights back to Instance mode at render time as render instances do not work in VFB/PV.

I am sure you can appreciate both options above are not ideal.

Another issue is with lights that are set to "Visible" seem to ignore the light select in multi pass. Take a look at the front lights in the light mix in the attached scene. This then means I have to ditch cloners altogether and have individual lights just so I can use light mix.
The light beams are correctly assigned but the visible "source" gets assigned to "rest unassigned" but that becomes an issue when I have lots of different visible lights all assigned to "rest".

I am hoping you can give some sort of indication on where you are with solving the issues relating to all this. Having had the same issues since Corona 3 I am getting a bit concerned that this is not a priority.
I appreciate that this might not affect other users as much as it does for me but I would like to know where I stand so I can make an informed decision about what I do going forward.

Thanks.

[Exactly]

Can someone from the development team please give a response to my post above from 2 weeks ago?

Thanks.

[burnin]

or
3. instead of "Corona Lights" use geo w/ Light Material on it. But now you can't use IES profiles.

[houska]

Hi Exactly and sorry for the delayed response.

The fact that render-instanced lights are working in IR is actually a mistake. You see, in C4D, lights can never be render-instanced, so when C4D prepares the lights for rendering at the beginning of the non-IR render, it does not create render-instanced lights. In IR, we make the render objects ourselves and we never realized that lights shouldn't have render instances. So far, we kept this as a feature, but I agree that it might be a bit confusing and we'll probably remove it.

We might create the render objects ourselves even in normal rendering, but there's high risk that we do something incorrectly (and C4D does not document the creation of render objects anywhere), so we'd rather not to. There's however another possible solution and that is force C4D handle our lights as objects. They would then behave exactly like objects with light material for all possible purposes.

As for the issue with the light emitter itself not appearing in the light select render pass, we'll check that and hopefully fix it, because to me it seems like a bug.
Edit: The issue has been confirmed as a bug and has been added to our bug tracking system. Internal tracking ID: 407347327

[Exactly]

Thanks for the reply Houska.

That all makes perfect sense now...and I guess it was the fact that it worked in the IR made me completely forget that C4D can't do render instances with lights...so yes, confusing indeed.

Glad the multi pass thing is confirmed as a bug. I will wait for the fix.

[Nejc Kilar]

Huh, one learns something new everyday... Thanks for the detailed explanation, Houska :) Also, thanks for opening up this topic Exactly, just ran into this today :)